I've tried to look for an in-game setting but i wasn't able to find it... Is there a command line argument maybe?
I'va also tried changin the language of the launcher and a few lines in the Ini file, but at no avail.

You have to change it from GOG Galaxy. Go to the BG 3 site. There is a little button right from the play button, where you can configure the game (labelled 'more'). Then push the button 'manage installation'. And then 'configure ...'. And voila, here you have the opportunity to change the language. Hope this helped.

I think when they said the DRM-free version, they meant the backup installer. I assume they're not using galaxy.

I don't have an answer, but I'd be willing to bet that Galaxy just changes a line in a config file somewhere. I don't know where that file is, though, nor do I know which line. Sorry :(

<?xml version="1.0" encoding="UTF-8" ?>
<save>
<header version="2" time="1534250670" />
<version major="3" minor="6" revision="0" build="3" />
<region id="Config">
<node id="root">
<children>
<node id="ConfigEntry">
<attribute id="MapKey" value="Language" type="22" />
<attribute id="Type" value="1" type="5" />
<attribute id="Value" value="English" type="20" />
</node>
</children>
</node>
</region>
</save>

That XML is in file ..\GOG Galaxy\Games\Baldurs Gate 3\Data\Localization when you change the language in Galaxy this line will change <attribute id="Value" value="English" type="20" />. EG changing to French sets the line to this <attribute id="Value" value="French" type="20" /> and downloads the French language pak ..\GOG Galaxy\Games\Baldurs Gate 3\Data\Localization\French\French.pak.

So if you are using the backup installer rather than Galaxy then you will need to change that lines value to the name of the language pak you want to use and the language pak needs to be in its own language folder in the Localization directory so for French it would be this ..Baldurs Gate 3\Data\Localization\French\French.pak.

Edit
I see TheEversor is from Italy so for Italian change the language line to this <attribute id="Value" value="Italian" type="20" /> and the language pak need to be in this path ,,\Baldurs Gate 3\Data\Localization\Italian\Italian.pak

Edit 2
Late entry I failed to name the xml file in the Localization directory that has the language flag. It is language.lsx the path is ..\Baldurs Gate 3\Data\Localization\language.lsx

Thank you so much for the replies, I didn't check the forum in a while... I guess the language pack is only installed via gog galaxy so my only option would be to find the language pack of the exact version I have the offline installer... This could be a little bit too tricky to be worth it.

you need a folder named with the option i.e, Italian and in that folder is the pak file which is really just a notepad file

yes you can download it from Galaxy... or get a pal to its just a few mb

and oldly it looks like captial letters matter in the folder name

It is not really tricky.
Steps:
1: Backup file ..\Baldurs Gate 3\Data\Localization\language.lsx.
2: Edit language.lsx and change <attribute id="Value" value="English" type="20" /> to <attribute id="Value" value="Italian" type="20" />
3: Create directory Italian in the Localization directory.
4: Drop Italian.pak in \Baldurs Gate 3\Data\Localization\Italian\.

If it does not work simply replace language.lsx with the backup to go back to English. You would not need to delete the Italian folder but I would just to tidy up.

All you need to do is get the language pak Italian.pak. I have not used the offline installers, but I am surprised that the localised language paks are not included in the download.

Not that odd, while you can ignore case when validating the files you install on windows exist, there is no need to as the windows file system preserves case. On other systems case can't be ignored.

BG3 runs on multiple systems so it makes sense to be case sensitive when validating installed files in code that can be common.

Yes, seems not included in the offline installer …
Else : game work good (on linux).

Hi,
There are only the English.pak with the installer in the Localization directory.

I use backup file with Lutris (GOG version).

Updating the lsx file didn't set to French (saty English)

Do you know if there are a way to get the language pack ?

PS : sorry for double post …

here; https://windowsforum.com/resources/french-folder-for-bg3.69/

Thank you : i get it with setup Lutris Galaxy version on another computer. Put French directlry in Localisation and update language.lsx

It's really a pity we don't have it in Offline files !

Hi,
Finally there are a way when you set up via OFFLINE files


After running the offline installer, select "Options" in the lower left corner, and then select the game language before the installation is initiated.

see all it took was to ignore Gog support and start fixing it ourselves ;)

now next step is to hack past the new Larian server in order to fix cross saves but thats a different can of worms

The « After running the offline installer, select "Options" in the lower left corner, and then select the game language before the installation is initiated.» sentence came from the link here : https://support.gog.com/hc/fr/articles/4412958845329-How-do-I-change-the-game-language?product=gog